feature: doubleclick on username to use it as a mention
feature: doubleclick on username to use it as a mention

a bit wonky and rough solution. It does what it is supposed to do, but
sometimes act a bit funky when e.g. inserting multiple names...  maybe
advertise as BETA feature for now? ;)

grubeninspekteur/BetterRBTV,grubeninspekteur/BetterRBTV,DoomDesign/BetterRBTV,DoomDesign/BetterRBTV